// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___RANGES_LAZY_SPLIT_VIEW_H
#define _LIBCPP___RANGES_LAZY_SPLIT_VIEW_H
#include <__algorithm/ranges_find.h>
#include <__algorithm/ranges_mismatch.h>
#include <__assert>
#include <__concepts/constructible.h>
#include <__concepts/convertible_to.h>
#include <__concepts/derived_from.h>
#include <__config>
#include <__functional/bind_back.h>
#include <__functional/ranges_operations.h>
#include <__iterator/concepts.h>
#include <__iterator/default_sentinel.h>
#include <__iterator/incrementable_traits.h>
#include <__iterator/indirectly_comparable.h>
#include <__iterator/iter_move.h>
#include <__iterator/iter_swap.h>
#include <__iterator/iterator_traits.h>
#include <__memory/addressof.h>
#include <__ranges/access.h>
#include <__ranges/all.h>
#include <__ranges/concepts.h>
#include <__ranges/non_propagating_cache.h>
#include <__ranges/range_adaptor.h>
#include <__ranges/single_view.h>
#include <__ranges/subrange.h>
#include <__ranges/view_interface.h>
#include <__type_traits/conditional.h>
#include <__type_traits/decay.h>
#include <__type_traits/is_nothrow_constructible.h>
#include <__type_traits/maybe_const.h>
#include <__type_traits/remove_reference.h>
#include <__utility/forward.h>
#include <__utility/move.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
namespace ranges {
template <auto>
struct __require_constant;
template <class _Range>
concept __tiny_range = sized_range<_Range> && requires {
typename __require_constant<remove_reference_t<_Range>::size()>;
} && (remove_reference_t<_Range>::size() <= 1);
template <input_range _View, forward_range _Pattern>
requires view<_View> && view<_Pattern> &&
indirectly_comparable<iterator_t<_View>, iterator_t<_Pattern>, ranges::equal_to> &&
(forward_range<_View> || __tiny_range<_Pattern>)
class lazy_split_view : public view_interface<lazy_split_view<_View, _Pattern>> {
_LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
_LIBCPP_NO_UNIQUE_ADDRESS _Pattern __pattern_ = _Pattern();
using _MaybeCurrent = _If<!forward_range<_View>, __non_propagating_cache<iterator_t<_View>>, __empty_cache>;
_LIBCPP_NO_UNIQUE_ADDRESS _MaybeCurrent __current_ = _MaybeCurrent();
template <bool>
struct __outer_iterator;
template <bool>
struct __inner_iterator;
public:
_LIBCPP_HIDE_FROM_ABI lazy_split_view()
requires default_initializable<_View> && default_initializable<_Pattern>
= default;
_LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 lazy_split_view(_View __base, _Pattern __pattern)
: __base_(std::move(__base)), __pattern_(std::move(__pattern)) {}
template <input_range _Range>
requires constructible_from<_View, views::all_t<_Range>> &&
constructible_from<_Pattern, single_view<range_value_t<_Range>>>
_LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 lazy_split_view(_Range&& __r, range_value_t<_Range> __e)
: __base_(views::all(std::forward<_Range>(__r))), __pattern_(views::single(std::move(__e))) {}
_LIBCPP_HIDE_FROM_ABI constexpr _View base() const&
requires copy_constructible<_View>
{
return __base_;
}
_LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }
_LIBCPP_HIDE_FROM_ABI constexpr auto begin() {
if constexpr (forward_range<_View>) {
return __outer_iterator < __simple_view<_View> && __simple_view < _Pattern >> {*this, ranges::begin(__base_)};
} else {
__current_.__emplace(ranges::begin(__base_));
return __outer_iterator<false>{*this};
}
}
_LIBCPP_HIDE_FROM_ABI constexpr auto begin() const
requires forward_range<_View> && forward_range<const _View>
{
return __outer_iterator<true>{*this, ranges::begin(__base_)};
}
_LIBCPP_HIDE_FROM_ABI constexpr auto end()
requires forward_range<_View> && common_range<_View>
{
return __outer_iterator < __simple_view<_View> && __simple_view < _Pattern >> {*this, ranges::end(__base_)};
}
_LIBCPP_HIDE_FROM_ABI constexpr auto end() const {
if constexpr (forward_range<_View> && forward_range<const _View> && common_range<const _View>) {
return __outer_iterator<true>{*this, ranges::end(__base_)};
} else {
return default_sentinel;
}
}
private:
template <class>
struct __outer_iterator_category {};
template <forward_range _Tp>
struct __outer_iterator_category<_Tp> {
using iterator_category = input_iterator_tag;
};
template <bool _Const>
struct __outer_iterator : __outer_iterator_category<__maybe_const<_Const, _View>> {
private:
template <bool>
friend struct __inner_iterator;
friend __outer_iterator<true>;
using _Parent = __maybe_const<_Const, lazy_split_view>;
using _Base = __maybe_const<_Const, _View>;
_Parent* __parent_ = nullptr;
using _MaybeCurrent = _If<forward_range<_View>, iterator_t<_Base>, __empty_cache>;
_LIBCPP_NO_UNIQUE_ADDRESS _MaybeCurrent __current_ = _MaybeCurrent();
bool __trailing_empty_ = false;
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto& __current() noexcept {
if constexpr (forward_range<_View>) {
return __current_;
} else {
return *__parent_->__current_;
}
}
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr const auto& __current() const noexcept {
if constexpr (forward_range<_View>) {
return __current_;
} else {
return *__parent_->__current_;
}
}
// Workaround for the GCC issue that doesn't allow calling `__parent_->__base_` from friend functions (because
// `__base_` is private).
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto& __parent_base() const noexcept { return __parent_->__base_; }
public:
// using iterator_category = inherited;
using iterator_concept = conditional_t<forward_range<_Base>, forward_iterator_tag, input_iterator_tag>;
using difference_type = range_difference_t<_Base>;
struct value_type : view_interface<value_type> {
private:
__outer_iterator __i_ = __outer_iterator();
public:
_LIBCPP_HIDE_FROM_ABI value_type() = default;
_LIBCPP_HIDE_FROM_ABI constexpr explicit value_type(__outer_iterator __i) : __i_(std::move(__i)) {}
_LIBCPP_HIDE_FROM_ABI constexpr __inner_iterator<_Const> begin() const { return __inner_iterator<_Const>{__i_}; }
_LIBCPP_HIDE_FROM_ABI constexpr default_sentinel_t end() const noexcept { return default_sentinel; }
};
_LIBCPP_HIDE_FROM_ABI __outer_iterator() = default;
_LIBCPP_HIDE_FROM_ABI constexpr explicit __outer_iterator(_Parent& __parent)
requires(!forward_range<_Base>)
: __parent_(std::addressof(__parent)) {}
_LIBCPP_HIDE_FROM_ABI constexpr __outer_iterator(_Parent& __parent, iterator_t<_Base> __current)
requires forward_range<_Base>
: __parent_(std::addressof(__parent)), __current_(std::move(__current)) {}
_LIBCPP_HIDE_FROM_ABI constexpr __outer_iterator(__outer_iterator<!_Const> __i)
requires _Const && convertible_to<iterator_t<_View>, iterator_t<_Base>>
: __parent_(__i.__parent_), __current_(std::move(__i.__current_)) {}
_LIBCPP_HIDE_FROM_ABI constexpr value_type operator*() const { return value_type{*this}; }
_LIBCPP_HIDE_FROM_ABI constexpr __outer_iterator& operator++() {
const auto __end = ranges::end(__parent_->__base_);
if (__current() == __end) {
__trailing_empty_ = false;
return *this;
}
const auto [__pbegin, __pend] = ranges::subrange{__parent_->__pattern_};
if (__pbegin == __pend) {
// Empty pattern: split on every element in the input range
++__current();
} else if constexpr (__tiny_range<_Pattern>) {
// One-element pattern: we can use `ranges::find`.
__current() = ranges::find(std::move(__current()), __end, *__pbegin);
if (__current() != __end) {
// Make sure we point to after the separator we just found.
++__current();
if (__current() == __end)
__trailing_empty_ = true;
}
} else {
// General case for n-element pattern.
do {
const auto [__b, __p] = ranges::mismatch(__current(), __end, __pbegin, __pend);
if (__p == __pend) {
__current() = __b;
if (__current() == __end) {
__trailing_empty_ = true;
}
break; // The pattern matched; skip it.
}
} while (++__current() != __end);
}
return *this;
}
_LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator++(int) {
if constexpr (forward_range<_Base>) {
auto __tmp = *this;
++*this;
return __tmp;
} else {
++*this;
}
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __outer_iterator& __x, const __outer_iterator& __y)
requires forward_range<_Base>
{
return __x.__current_ == __y.__current_ && __x.__trailing_empty_ == __y.__trailing_empty_;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __outer_iterator& __x, default_sentinel_t) {
_LIBCPP_ASSERT_NON_NULL(__x.__parent_ != nullptr, "Cannot call comparison on a default-constructed iterator.");
return __x.__current() == ranges::end(__x.__parent_base()) && !__x.__trailing_empty_;
}
};
template <class>
struct __inner_iterator_category {};
template <forward_range _Tp>
struct __inner_iterator_category<_Tp> {
using iterator_category =
_If< derived_from<typename iterator_traits<iterator_t<_Tp>>::iterator_category, forward_iterator_tag>,
forward_iterator_tag,
typename iterator_traits<iterator_t<_Tp>>::iterator_category >;
};
template <bool _Const>
struct __inner_iterator : __inner_iterator_category<__maybe_const<_Const, _View>> {
private:
using _Base = __maybe_const<_Const, _View>;
// Workaround for a GCC issue.
static constexpr bool _OuterConst = _Const;
__outer_iterator<_Const> __i_ = __outer_iterator<_OuterConst>();
bool __incremented_ = false;
// Note: these private functions are necessary because GCC doesn't allow calls to private members of `__i_` from
// free functions that are friends of `inner-iterator`.
_LIBCPP_HIDE_FROM_ABI constexpr bool __is_done() const {
_LIBCPP_ASSERT_NON_NULL(__i_.__parent_ != nullptr, "Cannot call comparison on a default-constructed iterator.");
auto [__pcur, __pend] = ranges::subrange{__i_.__parent_->__pattern_};
auto __end = ranges::end(__i_.__parent_->__base_);
if constexpr (__tiny_range<_Pattern>) {
const auto& __cur = __i_.__current();
if (__cur == __end)
return true;
if (__pcur == __pend)
return __incremented_;
return *__cur == *__pcur;
} else {
auto __cur = __i_.__current();
if (__cur == __end)
return true;
if (__pcur == __pend)
return __incremented_;
do {
if (*__cur != *__pcur)
return false;
if (++__pcur == __pend)
return true;
} while (++__cur != __end);
return false;
}
}
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto& __outer_current() noexcept { return __i_.__current(); }
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr const auto& __outer_current() const noexcept {
return __i_.__current();
}
public:
// using iterator_category = inherited;
using iterator_concept = typename __outer_iterator<_Const>::iterator_concept;
using value_type = range_value_t<_Base>;
using difference_type = range_difference_t<_Base>;
_LIBCPP_HIDE_FROM_ABI __inner_iterator() = default;
_LIBCPP_HIDE_FROM_ABI constexpr explicit __inner_iterator(__outer_iterator<_Const> __i) : __i_(std::move(__i)) {}
_LIBCPP_HIDE_FROM_ABI constexpr const iterator_t<_Base>& base() const& noexcept { return __i_.__current(); }
_LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_Base> base() &&
requires forward_range<_View>
{
return std::move(__i_.__current());
}
_LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator*() const { return *__i_.__current(); }
_LIBCPP_HIDE_FROM_ABI constexpr __inner_iterator& operator++() {
__incremented_ = true;
if constexpr (!forward_range<_Base>) {
if constexpr (_Pattern::size() == 0) {
return *this;
}
}
++__i_.__current();
return *this;
}
_LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator++(int) {
if constexpr (forward_range<_Base>) {
auto __tmp = *this;
++*this;
return __tmp;
} else {
++*this;
}
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __inner_iterator& __x, const __inner_iterator& __y)
requires forward_range<_Base>
{
return __x.__outer_current() == __y.__outer_current();
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __inner_iterator& __x, default_sentinel_t) {
return __x.__is_done();
}
_LIBCPP_HIDE_FROM_ABI friend constexpr decltype(auto)
iter_move(const __inner_iterator& __i) noexcept(noexcept(ranges::iter_move(__i.__outer_current()))) {
return ranges::iter_move(__i.__outer_current());
}
_LIBCPP_HIDE_FROM_ABI friend constexpr void iter_swap(
const __inner_iterator& __x,
const __inner_iterator& __y) noexcept(noexcept(ranges::iter_swap(__x.__outer_current(), __y.__outer_current())))
requires indirectly_swappable<iterator_t<_Base>>
{
ranges::iter_swap(__x.__outer_current(), __y.__outer_current());
}
};
};
template <class _Range, class _Pattern>
lazy_split_view(_Range&&, _Pattern&&) -> lazy_split_view<views::all_t<_Range>, views::all_t<_Pattern>>;
template <input_range _Range>
lazy_split_view(_Range&&,
range_value_t<_Range>) -> lazy_split_view<views::all_t<_Range>, single_view<range_value_t<_Range>>>;
namespace views {
namespace __lazy_split_view {
struct __fn {
template <class _Range, class _Pattern>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Pattern&& __pattern) const
noexcept(noexcept(lazy_split_view(std::forward<_Range>(__range), std::forward<_Pattern>(__pattern))))
-> decltype(lazy_split_view(std::forward<_Range>(__range), std::forward<_Pattern>(__pattern))) {
return lazy_split_view(std::forward<_Range>(__range), std::forward<_Pattern>(__pattern));
}
template <class _Pattern>
requires constructible_from<decay_t<_Pattern>, _Pattern>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pattern&& __pattern) const
noexcept(is_nothrow_constructible_v<decay_t<_Pattern>, _Pattern>) {
return __pipeable(std::__bind_back(*this, std::forward<_Pattern>(__pattern)));
}
};
} // namespace __lazy_split_view
inline namespace __cpo {
inline constexpr auto lazy_split = __lazy_split_view::__fn{};
} // namespace __cpo
} // namespace views
} // namespace ranges
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___RANGES_LAZY_SPLIT_VIEW_H
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